Hi,I'm not sure they need to be roll-up banners but just normal banners that can be wall mounted (hung down from wall or ceiling behind the speakers). It would be lovely if you can combine them with the Debian roll-up ones to save cost.
Reg. roll-up banners:http://berlindisplay.de/de/rollup-displays/rollup-eco-light-basic-850.html offers them for €39 net incl. p+p.
Kind regards, Daniel